import java.util.Scanner;
import java.util.TreeSet;

/**
 * Created with Intellij IDEA.
 * Description;
 * User:墨琦
 * Data:2023-09-25
 * Time:10:19
 * 删除公共字符
 */
public class Java_2 {
    public void method1()
    {
        Scanner in = new Scanner(System.in);
        String str1=in.nextLine();
        String str2=in.nextLine();

        TreeSet<Character> set=new TreeSet<>();
        for(int i=0;i<str2.length();i++)
        {
            if(!set.contains(str2.charAt(i)))
            {
                set.add(str2.charAt(i));
            }
        }
        String str3="";
        for(int i=0;i<str1.length();i++)
        {
            if(!set.contains(str1.charAt(i)))
            {
                str3+=str1.charAt(i);
            }
        }
        System.out.println(str3);
    }

    public void method2()
    {
        Scanner sc=new Scanner(System.in);
        String str1=sc.nextLine();
        String str2=sc.nextLine();
        String str3="";
        for(int i=0;i<str1.length();i++)
        {
            char s=str1.charAt(i);
            if(str2.indexOf(s)==-1)
            {
                str3+=s;
            }
        }
        System.out.println(str3);
    }
    public static void main(String[] args) {

    }
}
